The discussion below is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.
The present invention relates to engines of all sorts. More particularly, the present invention relates to an internal combustion engine of a barrel-type configuration in which the cylinder axes are arranged around a central longitudinal axis of the engine, and even more particularly to a barrel-type engine having a rotating cylinder bank.
Internal combustion engines have been around for a long time. The basic components of the engine are well known in the art and include the engine block, cylinder head, cylinders, pistons, valves, crankshaft and camshaft. The cylinder heads, cylinders and tops of the pistons typically form combustion chambers into which fuel and air are introduced so that combustion takes place. Useful work is generated from the hot, gaseous products of combustion acting directly on the top or crown surface of the piston. Generally, reciprocating linear motion of the pistons within the cylinders is transferred to rotary motion of a crankshaft via connecting rods. One common internal combustion engine is known as an Otto-type internal combustion engine and employs a four-stroke cycle in which power is derived from the combustion process over four separate pistons movements (strokes): intake stroke, compression stroke, expansion (power) stroke, and exhaust stroke. In traditional Otto-type automotive engine applications, the cylinders are typically stationary and are typically arranged in one of three ways: (1) a single row (in line) with the centerlines of the cylinders commonly vertically oriented; (2) a double row with the centerlines of opposite cylinders converging in a V (V-engine); or (3) two horizontal, opposed rows (opposed or pancake engine). Two additional Otto-type cylinder configurations were also experimented with, primarily between 1900 and 1950, and include (1) a radial configuration where the cylinder axes are arranged like spokes of a wheel with the lower rod ends mounted on a common crank shaft journal, and (2) a barrel configuration with cylinder axes arranged parallel around the central longitudinal axis of the engine. Barrel configurations generally include a stationary cylinder bank and the power is transferred to the crankshaft in one of three ways (1) with the lower ends of the connecting rods connected to a gear arrangement, (2) with the lower ends of the crankshaft connected to a wobble plate, and (3) with the lower ends of the rods pushing a cam surface.
A subclass of barrel engines are those with a rotating cylinder bank and such engines generally come in one of three configurations: (1) a two or four-cycle arrangement in which the rotating cylinder bank drives an angled thrust plate from which power is taken off as shown by way of example in U.S. Pat. Nos. 980,491; 1,345,808; 2,382,280 and 4,779,579; (2) a two-cycle arrangement in which a pair of rotating cylinder banks share a common cylinder head unit and in which the outer rod ends each drive an angled thrust plate as shown by way of example in U.S. Pat. Nos. 968,969; 1,255,664 and 1,779,032; and (3) a two-cycle arrangement in which a pair of rotating cylinder banks share a common piston and in which a pair cylinder head units are provided at each end thereof as shown by way of example in U.S. Pat. Nos. 3,830,208 and 5,103,778. It is believed, both radial and barrel engines, in particular, fell out of favor after World War II.
Beginning in the early part of the twentieth century, the conventional Otto-type reciprocating engine began to assume dominance as the most practical approach, even though it was recognized that the thermodynamic efficiency of the engine was such that about two-thirds of the energy developed through the combustion of the fuel was wasted. That is, roughly ⅓ of the fuel energy is delivered to the crankshaft as useful work, ⅓ is lost in waste heat through the cylinder walls, heads and pistons, and ⅓ is lost out of the exhaust.
The Wankel engine, which is also known as a rotary engine, is denoted as such because it utilizes a single triangular rotating piston which forms combustion chambers as it rotates within a stationary figure eight-shaped “cylinder”. The Wankel engine does not employ connecting rods as the rotating piston is linked directly to the crankshaft. The Wankel engine is also a four-stroke cycle engine, and while it has several advantages over the Otto-type engine, it produces higher emissions, has a shorter lifespan, and lacks torque at low speeds, which leads to greater fuel consumption.
Applicant's U.S. Patent Application Publication No. 2003/0131807 provides an improved barrel configuration with a rotating cylinder bank and angled thrust plate. However, it is always desirable to make improvements such as but not limited to improvements in thermodynamic efficiency, emissions, manufacturability, and/or power or torque of the engine.